[U-Boot] [PATCH 0/25] Introduce driver model support for SPI, SPI flash, cros_ec

[Simon Glass]

Hi Jagan,

On 11 August 2014 13:55, Simon Glass <sjg at chromium.org> wrote:
> Hi Jagan,
>
> On 10 August 2014 03:16, Jagan Teki <jagannadh.teki at gmail.com> wrote:
>> On Sun, Aug 10, 2014 at 2:59 AM, Simon Glass <sjg at chromium.org> wrote:
>>> Hi,
>>>
>>> On 14 July 2014 18:56, Simon Glass <sjg at chromium.org> wrote:
>>>> Up until now driver model has not been used for any type of bus. Buses
>>>> have some unique properties and needs, so we cannot claim that driver
>>>> model can cover all the common cases unless we have converted a bus over
>>>> to driver model.
>>>>
>>>> SPI is a reasonable choice for this next step. It has a fairly simple
>>>> API and not too many dependencies. The main one is SPI flash so we may
>>>> as well convert that also. Since the boards I test with have cros_ec I
>>>> have also included that, for SPI only.
>>>>
>>>> The technique used is make use of driver model's supported data structures
>>>> to hold information currently kept by each subsystem in a private data
>>>> structure. Since 'struct spi_slave' relates to the slave device on the bus
>>>> it is stored in the 'parent' data with each child device of the bus.
>>>> Since 'struct spi_flash' is a standard interface used for each SPI flash
>>>> driver, it is stored in the SPI FLash uclass's private data for each
>>>> device.
>>>>
>>>> New defines are created to enable driver model for each subsystem. These
>>>> are:
>>>>
>>>>    CONFIG_DM_SPI
>>>>    CONFIG_DM_SPI_FLASH
>>>>    CONFIG_DM_CROS_EC
>>>>
>>>> This allows us to move some boards and drivers to driver model, while
>>>> leaving others behind. A 'big bang' conversion of everything to driver
>>>> model, event at a subsystem level, is never going to work.
>>>>
>>>> On the other hand, we change the driver at the same time as the CONFIG
>>>> option is enabled. Keeping both version of the driver around involves a
>>>> flock of #ifdefs, the benefit of which is not apparent to me, since the
>>>> old code is removed anyway.
>>>>
>>>> There is some cost in changing the uclass interface after it is created,
>>>> so if you have limited time, please spend it reviewing the uclass
>>>> interfaces in spi.h and spi_flash.h. These need to be supported by each
>>>> driver, so changing them later may involve changing multiple drivers.
>>>>
>>>> To help with conversion of SPI drivers to driver model, documentation is
>>>> provided which takes the happy camper through the process with an example.
>>>>
>>>> As always, driver model patches are available at u-boot-dm.git branch
>>>> 'working'.
>>>>
>>>> Note: This series is not fully ready - e.g. some header files are missing
>>>> comments. But I wanted to get it out for review early since some SPI work
>>>> is ongoing which might depend on it.
>>>
>>> Are there any comments on this series please? I'd like to apply these
>>> to dm/master early next week, excluding the exynos ones.
>>
>> I will be busy in next full week, give me 2 more weeks.
>> Probably I will give my comments on next to next weekend.
>
> I'll see what I can do. It has been out for review for 4 weeks :-)

I'll send an updated series with your comments address. I'm planning
to apply the non-exynos parts of SPI this week. Please let me know if
you have any objections. I'd like to allow sufficient test time before
the release.

Regards,
Simon